As a conventional optical connector assembling method, one disclosed in Patent Literature 1 has been known, for example. The optical connector assembling method disclosed in Patent Literature 1 is one in which, while an optical cord is passed through a rear housing and a protection sleeve, a coated optical fiber exposed by removing an outer jacket of a leading end portion of the optical cord and a short optical fiber held by a connector ferrule are fusion-spliced to each other, the fusion-spliced part is covered with the protection sleeve, and then a plug frame and the rear housing are joined to each other, so as to be integrated with each other.
Patent Literature 2 discloses that, while a holding part of a ferrule holder (protection cap) is fitted onto a tubular part of a ferrule, a built-in optical fiber held by the ferrule and a coated optical fiber to be connected thereto are fusion-spliced to each other.